1. Field of the Invention
The present invention relates to a radial vibration detection apparatus, and in particular to a radial vibration detection apparatus that detects the radial vibration value of an optical assembly of an optical disc drive during optical assembly operation.
2. Description of the Related Art
Generally speaking, an optical disc drive includes an optical pick-up, a spindle motor, and a turntable, among other components. In order to rapidly and continuously access data in an optical disc during optical disc drive operation, the optical disc has to rotate at a high speed. When the optical disc rotates with the spindle motor, axial and radial vibration usually occurs, thereby causing focus and tracking errors in the optical pick-up on the optical disc.
Axial and radial vibration occurs due to several factors. For example, a bearing is not accurately assembled on the spindle motor, and the turntable for loading the optical disc is not correctly fitted in the bearing. Nevertheless, the design and manufacture of the bearing is enhanced. Thus, the axial and radial vibration is caused mainly by the assembly between the bearing and spindle motor or between the bearing and turntable rather than by the bearing itself.
Referring to FIG. 1, an optical assembly 5 includes a turntable 6 and a spindle motor 7. The turntable 6 is disposed on the spindle motor 7. The spindle motor 7 has a bearing (not shown) and is electrically connected to a circuit board 51. The turntable 6 has a body 61, a first part 61a and a second part 61b. An iron accommodating portion 62 is formed on the first part 61a of the body 61, and an iron element 63 is disposed therein. Additionally, five resilient clamp elements 64 are formed on the first part 61a and near the iron accommodating portion 62. The resilient clamp elements 64 protrude from the first part 61a and extend to the second part 61b in an equiangular manner. Thus, the body 61 is equally divided into five portions. The central hole of the optical disc is fitted onto the five clamp elements 64, and the optical disc is held thereby.
Usually, the turntable 6 is assembled on the spindle motor 7 by means of a punching process after the spindle motor 7 has been manufactured. At this time, assembling deviation is generated to enlarge the radial vibration, thereby causing manufacturing failure of the optical disc drive. In order to decrease or avoid the manufacturing failure of the optical disc drive, a detection device or process is needed on the production line. Specifically, the five resilient clamp elements 64 of the turntable 6 increase difficulty in detecting the radial vibration. Thus, a coordinate measurement machine or roundness measurement instrument is needed to detect the radial vibration. Nevertheless, the coordinate measurement machine or roundness measurement instrument is very expensive and the operation thereof is very complicated. Thus, detection of the radial vibration in the optical assembly 5 is inconvenient.
Hence, there is a need to provide a radial vibration detection apparatus to overcome the aforementioned problems. The radial vibration value of the turntable can be quickly and accurately detected on the production line. Meanwhile, the operation of the radial vibration detection apparatus is easy, such that defective optical assemblies are easily detected.